Machine tool table stop



March 20, 1945. M. WALTEI R 2,372,141

MACHINE TOOL TABLE STOP I Filed May 25, 1943 3 Sheets-Sheet 2 h "1' "'Lu' Ma Ar ME ISI I l l w L Q Q v JZJH/V M WHLTER.

8 INVENTOR.

- BY @Zuu 9 w 3 Sheet-Sheet 3 J. M. WALTER MACHINE TOOL TABLE STOP Filed May 25. 1943 March 20, 1945.

HHU

INVENTOR. BY Claw JEN/v M WHLTER.

Patented Mar. 20, 1945 MACHINE TOOL TABLE STOP John M. Walter, Cincinnati, Ohio, assignor to The G. A. Gray Company, Cincinnati, Ohio, a

corporation of Ohio Application May 25, 1943, Serial No. 488,368

teams. (01. 90-58) In machine tools having traveling tables, such for example as metal planers, thetables on occasion are not stopped at the end of a traverse thereof, and continue by inertia to move beyond the supporting bed on which they are mounted and guided. Thus if a direct connected motor drive fails to stop, and the large gear wheel or bull wheel of a planer continues to rotate, the table may continue to move, with the rack' out of mesh with the bull wheel, and entirely out of control of the operator.

In large planers where the table is very heavy, and 'runs away or coasts on its support, great danger may arise. The tables may coast as far as 25 feet beyond the normal limit of movement, and with higher platen speeds such as are being developed at present, even greater movement can .be expected.

Present table speeds run to 240 feet per minute,

and the tables will exceed fifty tons in weight. The force with which they move by inertia at the end of a stroke is in proportion directly to their mass and as the square of their speed. Thus an said stops supplied with springs forty-three inches 7 lon and made of one and one-quarter inch spring steel, calculated to support a load of 14,000 pounds each; On the same calculations, for a like table having a maximum speed of 240 feet per minute, the springs would have to be built to take a. load of 65,000 pounds each. l

It is the object of my invention to provide a very simple and inexpensive stop, of little bulk, and highly effective. To this end I provide on the table and on the bed which supports it respective elements in the form of a block or blocks which are to be cut, and tools which are to cut into the blocks. In other words, if the table runs out of mesh with the drive, a force will be applied to stop the table, arising from the reactance of tools cutting into the blocks. This occurs without undue impact.

stop can be appreciated when I note that in a test, using my stopping devices, a table of 42 tons in weight, running at 240 feet per minute as it came out of driving mesh with the bull wheel, was stopped in nine inches.

Various modes of mounting the tools and mounting the blocks may be provided and it makes no difference whether the tool mounting is on the table or the bed, providing that the blocks into which the tools out are mounted on the other of the two members. Or the arrangement could be alternative, one cutting tool arrangement at one side of the bed to engage a block on the table, and a block on the other side of the bed to'engage a tool on the table. Again, a self-contained block and tool combination may be provided, normally free of one of the members, but interposed for example as a stop in the path of the table, or of one or more lugs beneath the table. Tools can be mounted on the table so as to out directly, on the bed, or on a block-like protruberance integrally formed on the bed, or tools mounted on the bed can be positioned to cut the table casting; but the convenience of providing renewable blocks to be cut will be evident. Moreover the blocks may be so designed as to be capable of repositioning so that each block may be used to'present a plurality of fresh cutting surfaces.

Ordinarily for a large planer there will be a cutting tool and cutting block arrangement for each of the four corners. Tools may be arranged in a gang of several tools, so as to take too much load from a single tool, and indeed various modifications may be desirable, depending upon the structure of the machine and the convenience in arranging the emergency stopping devices.

In the drawings I have shown several modifications, without intent however to limit the possible variations, for the purpose of explaining my invention by several examples, the novelty thereof being set forth in the appended claims.

In the drawings:

Figure 1 is a plan view of a planer table and bed, showing the stopping device mounted altoether on the bed, but arranged to be picked up by lugs located on the underside of the platen or table.

Figure 2 is a side elevational detail showing the table, lug and stopping device.

Figure 3 is a section on the line 33 f Figure 5.

Figure 4 is a section on the line 4-4 of Figure 3.

Figure 5 is a section on the line 5-5 of Figure 3, the group of figures showing the arrange- ..and the bed at '2.

ment for mounting the stopping device entirely on the bed, the relation of the table thereto being one of abutment, if it runs beyond the driving means.

Figure 6 is a plan view illustrating a structure in which the cutting tools are mounted on the underside of the table, and the blocks to be out are on the bed.

Figure '7 is fa'detail cross sectionshowing the tool holder, cutting tool and block against which the cutting is performed at one end of the machine.

Figure 8 is a like View showing the arrangement on the opposite end of themachine.

Figure 9 is a plan view of a planer table and bed showing yet another arrangement of tools and blocks.

Figure 10 is a side elevation thereof.

Figure 11 is a partial end elevation thereon on an enlarged scale.

"Figure 12 is .apartial sideelevation thereof.

Referring to the first modification, shown gen- .erally in Figures 1 and 2 and detailed in'Figures '3 to 5 inclusive, a structure is indicated whichis recommended in instances where it is 'not convenient to get .at the'underside of the"tab1'e,'but Where the bed has spaces for'the mounting of the stopping devices. The table is indicated at I There are two abutment *lugs provided on the underside of the table as'at 6 and I one for coacting with thestopping device :at each end of the stroke or traverse of the table.

"There will be generally similar stopping devices'at each end of the bed, one inalignmentwith'e'ach lug. A stopping device is indicated generally at B in'Figures 1 and 2.

As detailed in Figures 3, 4 and 5 each stopping device consists of a pair of parallel spaced metal blocks 9, 9. Guide blocks I0, H] are locatedabove them, and are shaped to provide a channel in which a'tool holding slide H is slidably mounted. The-spaced blocks and the guide blocks'are bolted *to-the bed 2 as shown.

The slide 11 has mounting means to hold 'a 'pair of tools 13 *and I4, one on each side, the tools being arranged to 'cut into the blocks 9 at theirinner'faces. Theslide may be perforated or recessed to receive thetools, whichcan be held in place by means of set screws 15 and HE. A protuberance-or abutment F2 on the underside of the slide acts as a backstop for the tools. It may be noted'that the blocks 9 can-be initially cut'away'or relieved as at 9a so that 'thes'lide H can lie within the length of the guides 1-0. A

loose sheet metal cover may be placed overthe assembly'to protect it from the accumulation of foreign material.

As has been indicated, the slide H is so located that, should the table escapefrom 'its'dri-ve and start running 1oose,'the lug 1 will strike the slide and moveit toward the end 'oftheb'ed. This causes the tools to cut into the .two parallel blocks 9, and dissipates the kinetic energy 'in the escaped table in the cutting-operation. The resuit is to stop the escaped table in a very short .space and with relatively little jarring.

In Figure 6 a pair of blocks 11 are bolted .to the bed at one end While at the other end there are fastened another pair of blocks 18 more widely spaced. The latter .blocks may be bolted to the side rails of the bed as indicated in Figure -'7. While slightly different .arrangementsof tools and blocks have beenshown .at eitherrend'of the table and .bed (and .as detailed in Figures 7 and 8), the arrangement at both ends may be identical.

Near one end of the table, and beneath it, tools are fastened as at 20 in Figure 6, the tools being so spaced that each of them will cut one of the blocks I! if the table I moves far enough to the right in Figure 6. Another pair of tools is mounted at the position indicated at 2| in Figure 6 so that these .toolscan cutithe blocks l8 if the table moves'iar enough to the left.

The construction and mounting of the tools "can be considerably varied. In Figure 7 a tool holder block 2Ia is shown bolted to the underside of the table. This block is recessed to accept the tool proper, indicated at 22, and the tool is held in place by 'a clamp 23 and bolts 24, and forced against an abutment on the block 21a by asset-screw'Zi.

Yet another modification is shown in Figures 9 to '12 inclusive. Here a pair of blocks 26 are bolted to the outside rails of the bed near one end thereof. The tools are mounted on the tablein the position indicated at 21, and near one end When this is done, those blocks left in Figures 9 .and .10 may be located intermediate the ends of the table in the position .shownatZB.

In this modification the two tools at each side of the table are located close together and may be fastened against the same tool block 29 as shown in Figure 12, the tools being engaged in :recessesin the block and being held by clamping means indicated at 30 .and -3 l One of the tools "32 has its cuttingface so directed as-to out into the block'ZS at one end of the bed. The other tool 33 is so directed as to cut into the opposite b'lock'at 28.

Whether the stopping means for each corner of the table are provided or just one stopping device at either end, where'the stopping devices are located or how arranged is a matter of preference, the point being that when the table escapes, a tool at once begins cutting against an emergency cutting block, thereby stopping the 'table.

Having thus described my invention what I claim as new and desire tosecure by'Letters Patcuttingtoolelement and a cutting block element,

:one of these elements-undercontrol of the table .and one of them-under control of the bed, lo-

-:cated so'thatlupon 'theescape of the table its momentum will-be expended in'a cutting operation by :said -'tool e'lementupon'the cutting block ele- :ment.

.2 In a device having a bed and a table driven :along said bed, means for stopping the movement of the table should it escape from drive controliatrthe end of :its stroke, said means comprising :a'cutting-toolelementand a cutting block element-one of these elements under control of .thetableandone of them under control of the bed locatedso that upon the escape of'the table its momentum will be expendedin acutting operation by said .tool element upon the cutting blockelement, the cutting tool element consisting of a .plurality'of tools, so that the :cut will be dividediamong the said tools.

3. In a device having a bed and a table-driven along :said bed, means :for stopping the movement of the table should it escape from drive control at the end of its stroke, comprising a cutting tool element and a cutting block element, one mountedon the table and one on the bed and arranged to come into operative cutting relationship promptly upon the .escape of the table, whereby the table movement will be expended in the operation of forming a cut by said tool element.

4. In a device having a bed and a table driven along said bed, means for stopping the movement of the table should it escape from drive control at the end of its stroke, comprising a cutting tool element and a cutting block element,

one mounted on the table and one on the bed and arranged to come into operative cutting relationship promptly upon the escape of the table, whereby the table momentum will be expended in the operation of forming a cut by said tool element, there being a cutting tool element and block element for each of the four corners of the table.

5. In a device having a bed and table driven along said bed, means for stopping the movement of the table should it escape from drive control at the end of its stroke, comprising a cutting tool element and a cutting block element, one mounted on the table and one on the bed and arranged to come into operative cutting relationone mounted on the table and one on the bedand arranged to come into operative cutting relationship promptly upon the escape of the table, whereby the table movement will be stopped in the operation of forming a cut by said tool element, the cutting tool element comprising a plurality of tools.

'7. In a device having a bed and a table driven I along said bed, means for stopping the movement of said table should it escape from the drive control at the end of its stroke, comprising a protuberance on the table forming a portion to be out against and a cutting tool means mounted on said bed and arranged to come into operative cutting relationship with said portion of said table, promptly upon escape of said table, whereby the table movement will be stopped in the operation of forming a cut by said tool means.

8. In a device having a bed and a table driven along said bed, means for stopping the movement of said table should it escape from the drive control at the end of its stroke, comprising a protuberance to be out against on the bed, and a' cutting tool means mounted on said table and arranged to come into operative cutting relationship with said portion of said bed promptly upon escape of said table, whereby the table movement will be stopped in the operation of I forming a cut by said tool means.

9. In a device having a bed and a, table driven along said bed, means for stopping the movement of said table should it escape from drive control at the end of its stroke, comprising cutting tool means rigidly connectedwhen in use with one of said element, and arranged to come into operative cutting relationship with material to be cut against, rigidly connected when in use with the other of said elements, promptly upon escape of said table, whereby the table movement will be stopped in the operation of forming a cut, by said tool means,

JOHN M. WALTER. 

